Means for polishing multifocal lenses



L. w. BUGBEE. MEANS FOR POLISHING MULTIFOCAL LENSES.

APPLICATION FILED MAR. 22, 1920.

1 ,406,927, Patented Feb. 14, 1922.

2 SHEETS-SHEET I.

INVENTOR. Lac/4n 11/. 61/6056.

ATTORNEY5.

L. W. BU-GBEE.

MEANS FOR POLISHING MULTI FOCAL LENSES.

APPLICATION man MAR 22. 1920.

1 ,406,927, Patented Feb. 14, 1922.

2 SHEETSSHEET 2.

I NV EN TOR.

1. ucl/m' W 50655! ATTORNEY-S.

UNITED STATES PATENT OFFICE.

LUGIAN W. BUGBEE OF INDIANAPOLIS, INDIANA, ASSIGNOR 'IO CNEIIECE BIFOCALLENS COMPANY, 013 INDIANAPOLIS,INDIANA, CORPORATIOIL. I

; MEANS FOR POLISHING MULTIFOGAL LENSES.

Specification of Letters Patent.

Patented Feb. 14, 1922.

.Applicationfiled March 22, 1920. Serial No. 367,754.

To all whom it may concern: 7 7

Be it known that I, LUCIAN \V. BUGBEE, a citizen of the United States,and a resident of Indianapolis, county of Marion,. and

State of Indiana, have invented a certain new and useful Means forPolishing Multifocal Lenses; and I do hereby declare that the followingis a full, clear, and exact description thereof, reference being had tothe accompanying drawings, in which like numerals refer to like parts.

The object of this invention is the improvement of the polishing ofsurfaces of bifocal lenses or any lenses having a plurality of surfaces,and relates particularly to means for positively rotating a plurality ofpolishers which are held in place loosely by pins. In such polishingmechanism the lens holder is rotated and will. to some extent, causerather uncertain and independent described. In the construction in myformerapplication. a belt extends around the two polishers or buttons sothat the rotation of one polisher influences the rotation of the otherand tends to produce uniformity of rotation and action. The specificimprovement herein oversaid former construction consists in anindependent positively driven pulley and a belt extending around saidpulley and said. plurality of polishers or buttons sothat they will bothpositively rotate.

The full nature of the invention will be understood from theaccompanying drawings and the following description and claims:

In the drawings, Fig. 1 is'a side elevation of a portion of a lenspolishing machine including this invention. Fig. 2 is a plan view ofwhat is shown in Fig. 1. Fig. 3 is a vertical sectional. view throughparts of the machine showing the lens blank and holder in centralvertical section, the remaining parts being in front elevation andpartially broken away. Fig. l is a plan view of the lens. polishers andmeans for rotating the same that is shown in the other figures, thepin-carrying means and other mechanism being not shown. Fig. 5 isthesame as F ig. 4 illustrating a modified form where only the outerpolisher is driven.

There is shown in Figs. 1 and 2 parts of a machine in connection withwhich this invention has been and can beused, although mostparts of themachine are old. There is shown .a ta blelO with a vertical shaft 11mounted in the bearings 12, said shaft carrying a removable lens holder13 of common type on which a target lens blank 1-1 is secured fortreatment. The shaft 11 is driven by means of a pulley. 15 and belt 16.011 said table there is a base plate 110 carrying stationary bearingposts 17 carrying bearings 18 in which bearing screws 19 arehorizontally mounted, as shown in Fig. 2, in connection with which thearm or frame 20 is pivoted at its rear end and its front end is actedupon by gravity for exerting pressure on the polishing means or buttons.The gravity can be increased by adding additional weights, not shown, asis often done in the practice. 7

In F ig. 3 there is shown a front elevation of the front end of the arm20 which has a segmental-shaped plate 24 rigid therewith. The clampingplate 25 is associatedsurface of the lens blank. and the surroundingannular area 31, which is the distance surface of the lens blank. Thesetwo surfaces appear in Fig. 4, and are there shown separated by a(llVlSlO-Il line 32. although in the actual lens said division line ispractically invisible. For polishing the central or reading surface 30 asmall button 35 is surface 81 between the edge of the blank and thereading surface. Said blank is what is known in the trade as a targetlens bifocal blank. Said two surfaces have been generated to give themthe proper relative curvatures, prior to'the polishing operation by themeans herein set forth.

The lens holder and lens are and the polishing buttons 35 and 36 areheld in place by pins37 and 38, respectively, arranged so as to permitthe polishing buttons to revolve on the lens blank as they may be causedto revolve by the rotation of the blank. This usually gives sufiicientrevolution of the buttons to cause the desired cross rubbing, as thebuttons will rotate almost at the speed of the lens blank at its line ofcontact with the polishing button farthest from the center of the lensblank.

The pins 37 and 38 are secured in bar 40 pivoted by a pin ell to thelower end of the rod 26. This enables the bar 40 to rock and permit thepolishing buttons to fully engage and accommodate themselves to thesurfaces of the blank during the polishing operation, and the wei ht ofthe arm 20, red 26, bar 40 and pins and 38 will be constantly exerted onthe polishing buttons in order to cause the friction desired for thepolishing action.

In order to cause an equivalent polishing action by the two buttons, thebar 40 is provided with a number of holes 42 so that it of the largebutton 36 are not relatively great, the outer portion of said buttondoes not always rotate with the blank in the direction of the arrow andit is desirable for that button to always rotate to effect crosspolishing. Therefore, the two buttons or polishers are preferablyrotated positively by a belt 50 operating in grooves 51 and driven by adriving pulley 52 mounted on the upper end of a shaft 53 having hearingsin the base plate 110 and a bearing arm 111 anddriven by a pulley 56landbelt 55. This Jlll cause both polishers or buttons to rotate and torotate in the same direction and in the direction in which the rotarymovement of the blank tends to cause the small polisher or button torotate.

rotated In the modified form shown in Fig. 5, only the outer polisher orbutton 36 is rotated positively by the belt 50 and in the directionshown. This is also a very satisfactory arrangement for it determinespositively both the rotation and direction of rotation of said largebutton and it is of much less impor' tance to positively drive the smallbutton than the large one, for the small button will always be rotatedby the lens blank.

Since the blank under the outer edge of the small button travelsinfinitely faster than the portion under the inner edge of said but ton,which is at the center of the lens blank, the lens blank always causesthe outer portion of the inner button to rotate in the same direction asthe blank. Ifthe pnlley 52 is adjusted as to it speed properly, in ratioto the speed of the lens blank holder, the two Polishers or buttons inthis last described arrangement can be caused to polish the differ'entsurfaces with a substantially uniform efl'ect.

The invention claimed is:

1. The combination with a lens holder for holding a plurality ofconcentric lens blank surfaces to be polished, and means for rotatingthe same, of a polishing button for each surface thereof, a pin framehaving a pin for loosely engaging each button, vertically movable meansto which said pin frame is pivoted between the pins so the pin frame canrock thereon vertically, and a single independently driven beltextending around all of said polishing buttons for positively rotatingthem simultaneously.

2. The combination with a rotary lens holder adapted to hold a lensblank having a central portion and a surrounding annular portion, of apolishing button for the surrounding annular portion with a diametersubstantially the same as the width of said surrounding portion, apolishing button for the inner portion having a diameter substantiallyone-half of said portion, a pin frame with a pin engaging each of saidbuttons and arranged so as to hold the button for the inner portionbetween the center and circumference of said, portion and to hold thebutton for polishing the outer portion between the inner and outerperipheries of said portion and to hold said two buttons on oppositesides of the center of the central portion, vertically movable means towhich said pin frame is pivoted between the pins so that it can rockvertically, and a single independently drivenbelt extending around allof said polishing buttons for positively rotating them simultaneously.

In witness whereof, I" have hereunto affixed my signature.

LUOIAN lV. BUGBEEL

